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Suvorava T, Luksha L, Bulanova KY, Lobanok LM. Dose-rate dependent effects of ionizing radiation on vascular reactivity. Radiat Prot Dosimetry 2006; 122:543-5. [PMID: 17132674 DOI: 10.1093/rpd/ncl432] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
This study was designed to investigate the dose-rate dependent effects of ionising radiation on endothelium- and NO-mediated reactivity of aorta and coronary vessels. Rats were exposed to acute ((137)Cs, 9 x 10(-4) Gy s(-1), 18 min) and chronic ((137)Cs, 2.8 x 10(-7) Gy s(-1), 41 days) radiation in 1 Gy dose. Acute irradiation transiently increased coronary flow in eNOS-activity-dependent manner on day 3 after exposure. In striking contrast, chronic irradiation caused a significant depression of coronary flow even on day 90 after irradiation and abolished the effects of NO-synthase inhibitor N-nitro-L-arginine methyl ester (10 micromol l(-1)). Furthermore, low intensity radiation strongly diminished the vasodilator properties of NO-donor sodium nitroprusside (5 micromol l(-1)). A similar pattern was observed in aortic rings. Endothelium-dependent vasodilation was increased on days 3 and 10 after acute irradiation, but strongly inhibited following chronic exposure for the entire post-radiation period. This was accompanied by a diminished vasodilator response to NO-donor on days 3, 10 and 30 of post-radiation but not on day 90. The data suggest that ionising radiation in 1 Gy induces changes of aortic and coronary vessels reactivity depending on the dose-rate and the interval after exposure.
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Affiliation(s)
- T Suvorava
- Institute of Radiobiology, National Academy of Sciences of Belarus, Fedyuninskogo street 4, 246007 Gomel, Belarus
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Suvorava T, Luksha LS, Lobanok LM. The effects of acute and chronic radiation on endothelium- and no-dependent vascular reactivity. Cell Mol Biol (Noisy-le-grand) 2005; 51:321-7. [PMID: 16191400] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2004] [Accepted: 12/29/2004] [Indexed: 05/04/2023]
Abstract
Endothelium- and NO-dependent relaxation of aortic segments and basal coronary flow and response of coronary vessels to exogenous NO in the Langendorff-perfused rat hearts were examined on the 3rd, 10th, 30th and 90th days following whole body irradiation in 1 Gy dose with different dose rate. NO-mediated elevation of coronary flow and increased aortic endothelium-dependent vasodilation were found at the early stage after acute irradiation (137Cs, 9 x 10(-4) Gy/s), while vascular reactivity to exogenous NO was not changed. Chronic irradiation (137Cs, 2.3 x 10(-7) Gy/s) significantly impaired endothelium-dependent relaxation within whole experimental period and decreased NO component of basal coronary flow at the 3rd, 10th and 90th day. It was associated with attenuated reactivity to NO-donor in aorta one month after irradiation and in the coronary vessels--shortly after irradiation. In the delayed period endothelial dysfunction and the diminution of NO-dependent coronary flow were mediated by selective impairment of NO synthesis/release. Decreased survival rate of the lethally-irradiated Nwnitro-L-arginine methyl ester-treated animals revealed radiosensitizing properties of NO synthase inhibition. The data obtained indicate the involvement of NO in the alterations of vascular reactivity depending on the dose rate and on the interval after the irradiation.
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Affiliation(s)
- T Suvorava
- Department of Cardiovascular Physiology, Institute of Radiobiology, National Academy of Science of Belarus, Gomel, Belarus.
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Lobanok LM, Suvorova TA. [Role of NO-mediated mechanisms in post-irradiation changes of neurohormonal regulation of the heart function]. Radiats Biol Radioecol 2004; 44:312-8. [PMID: 15287261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/30/2023]
Abstract
Investigations on isolated Langendorff-perfused rat heart have shown that after the impact of ionizing radiation in 1 Gy dose the myocardial contractility and relaxation are decreased. The inhibition of NO synthesis attenuates chrono- and inotropic responses of the heart and reaction of coronary vessels to norepinephrine (NE), increases negative inotropic and vasoconstrictor effects of carbamylcholine (CCh). In the irradiated animals the reaction of isolated heart to NE and CCh is decreased. The post-irradiation changes in adreno- and cholinoreactivity caused not only by changes in receptor sensitivity and density, but also by impairment of NO-mediated regulation of coronary flow and biomechanical heart function.
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Bulanova KI, Lobanok LM. [Systemic approach to radiobiological studies]. Radiats Biol Radioecol 2004; 44:5-14. [PMID: 15060932] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/29/2023]
Abstract
The principles of information theory were applied for analysis of radiobiological effects. The perception of ionizing radiations as a signal enables living organism to discern their benefits or harm, to react to absolute and relatively small deviations, to keep the logic and chronicle of events, to use the former experience for reacting in presence, to forecast consequences. The systemic analysis of organism's response to ionizing radiations allows explaining the peculiarities of effects of different absorbed doses, hormesis, apoptosis, remote consequences and other post-radiation effects.
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Affiliation(s)
- K Ia Bulanova
- Institute of Radiobiology, National Academy of Science of Belarus, Gomel, Belarus
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Lobanok LM, Solov'eva NG. [Age related features of postradiation changes of functional activity of local vascular renin-angiotensin system]. Radiats Biol Radioecol 2003; 43:404-11. [PMID: 14608671] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/27/2023]
Abstract
The postradiation changes of constriction effects of angiotensin II (Ang II) and angiotensin I (Ang I) on isolated preparations of thoracic aorta young and old rats which underwent gamma-irradiation in dose 1 Gy (137Cs, 9 x 10(-4) Gy/s) were investigated. It has been found, that the aging leads to the alteration of angiotensin receptors, which appears as changes in their density and/or sensitivity to action of agonist. With increase of age the activity of angiotensin-converting enzyme (ACE) in the wall of aorta is oppressed, and as a result, the level of local formation of Ang II and the constriction, caused by it are reduced. The inhibitory influence of endothelium on vasoconstriction effects of Ang II and Ang I in ontogenesis does not change. The influence of gamma-radiation in a dose of 1 Gy modifies the functional activity of the local vascular renin-angiotensin system (RAS): the sensitivity and/or density of angiotensin receptors and the activity of ACE increased the dilatation influences of endothelium were oppressed mainly for account of easing the synthesis of NO. The duration of postradiation infringements of functional activity of local vascular RAS in many respects are determined by the stage of ontogenic development of irradiated organism.
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Affiliation(s)
- L M Lobanok
- Institute of Radiobiology, National Academy of Sciences of Belarus, Minsk, 220141 Belarus
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Lobanok LM, Luksha NP. [Influence of hypoxia and anoxia on endothelium-dependent dilatation response of rat's aorta exposed to low-intensity gamma irradiation]. Radiats Biol Radioecol 2002; 42:498-502. [PMID: 12449816] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/27/2023]
Abstract
The study of isolated segments of aorta has shown that prolongated exposure of rats to gamma-radiation with 50 cGy dose (with a dose rate of 2.8 x 10(7) Gy/s) causes the decrease in endothelium-dependent dilatation responses to M-cholinoreceptors stimulation. During oxygenation the post-radiation changes are displayed within one month, and under functional loads, specifically, during perfusion by hypoxic and anoxic solutions--in more remote terms of the post-radiation period.
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Affiliation(s)
- L M Lobanok
- Institute of Radiobiology, Belarus Academy of Sciences, Minsk, 220041 Belarus.
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Lobanok LM, Antonenko AN. [Effect of prolonged gamma-irradiation on the functional state of heart and its adrenergic regulation at hypothyroidism]. Radiats Biol Radioecol 2001; 41:10-5. [PMID: 11253689] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Abstract
The study of heart isolated by Langendorf's method has shown that the prolongated gamma-irradiation of euthyroid rats in 1.0 Gy dose (2.8 x 10(-7) Gy/sec) causes the decrease in contraction ability, myocardium relaxation and functional response of heart to the stimulation of beta-adrenergic receptors, and the increase in myocardium reaction to the stimulation of alpha-adrenergic receptors. The irradiation of hypothyroid animals leads to more significant and long changes in contraction function of heart and its adrenergic regulation.
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Affiliation(s)
- L M Lobanok
- Institute of Radiobiology, National Academy of Sciences of Belarus, Minsk, 220141 Belarus
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Lobanok LM, Antonenko AN. [The biomechanical function of the heart and its adrenergic regulation after long-term gamma radiation exposure]. Radiats Biol Radioecol 2000; 40:245-9. [PMID: 10907398] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
The study of heart isolated by Langendorf's method has shown that the prolonged gamma irradiation of rats with 1.0 Gy dose (2.8 x 10(-7) Gy/sec) causes the decrease in contraction and relaxation ability, of myocardium, reduces functional response of heart to the stimulation of beta-adrenergic receptors, and increases of myocardium reaction to the stimulation of alpha-adrenergic receptors.
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Affiliation(s)
- L M Lobanok
- Institute of Radiobiology, National Academy of Science of Belarus, Minsk.
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Bulanova KI, Komar ES, Lobanok LM. [The aspects of adenylate cyclase activity regulation in myocardium cell membranes during hypokinesia]. Aviakosm Ekolog Med 1999; 33:43-7. [PMID: 10530385] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/14/2023]
Abstract
Nonstimulated and isoproterenol, GTF, GITF, NaF stimulated activities of the adenylate cyclase in sarcolemma in white rats' myocardium was studied after two weeks of hypokinesia. As was established, in restrained animals the sensitivity of adenylate cyclase to the specified agents was increased and transition to the bimodal GTF regulation took place. It is hypothesised that involvement of membrane-bound Gi-proteins in the adrenergic effects on cardiomyocytes is one of mechanisms of the cardiotropic effects of restraint and heart distresses.
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Petrashevskaia NN, Malykhina AP, Sidorov AV, Lobanok LM. [The effect of stimulation of the adrenergic receptors on the frequency depression of the temporal parameters of the action potential in the right atrium of rats]. Ross Fiziol Zh Im I M Sechenova 1999; 85:554-60. [PMID: 10513390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/14/2023]
Abstract
At a stimulation rate of 1 Hz, activation of alpha-adrenoreceptors prolonged the AP duration at 10%, 50%, and 90% repolarisation at 10(-7), 10(-6) M in the rat isolated right atria, but shortened it at a higher concentration of 10(-5) M. The frequency-induced depression of the AP duration became more evident in cardiomyocytes stimulated by 10(-7), 10(-6) M and less obvious at 10(-5) M of alpha-adrenoagonist. Activation of alpha-adrenoreceptors by isoprenalin shortened the AP duration and enhanced the stimulation-rate-dependent changes in the atrial AP configuration.
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Luksha LS, Lobanok LM. [Aorta dilatation after prolonged gamma-irradiation]. Radiats Biol Radioecol 1998; 38:510-5. [PMID: 9765668] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
It is shown on isolated aorta preparations that prolonged gamma-irradiation of rats results in depression of endothelium-dependent and endothelium-independent vasodilatation responses to beta-adrenoceptors stimulation by isoprenaline and M-cholinoceptors by carbachol.
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Affiliation(s)
- L S Luksha
- Institute of Radiobiology, Belarus Academy of Sciences, Minsk
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Lobanok LM, Malykhina AP. [Effects of prolonged gamma irradiation and hypoxia on bioelectrical activity of myocardial cells]. Radiats Biol Radioecol 1998; 38:201-6. [PMID: 9633622] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
It was established that prolonged gamma-irradiation of rats leads to the decrease of amplitude and duration of action potentials of right atrial cells, attenuation of the dependence of these electrophysiological characteristics upon the stimulation frequency, depression of the interval of cardiomyocytes reaction on the hypoxia. The revealed post-radiation changes determine the reduction of function resistance of heart cells bioelectrical activity and promote the initiation of arrhythmias.
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Affiliation(s)
- L M Lobanok
- Institute of Radiobiology, National Academy of Science of Belarus, Minsk
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Luksha LS, Lobanok LM. [The intensification of the vasodilator reactions of arterial vessels to stimulation of the beta-adrenergic receptors in the postradiation period]. Radiats Biol Radioecol 1995; 35:264-268. [PMID: 7757191] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
It was shown with endothelium-containing and endothelium-denuded aorta segments that external gamma-irradiation of rats (6.0 Gy) results in intensification of vasodilatation reactions on beta-adrenoceptor stimulation by isoprenaline with maximum in 30th day of post-radiation period. This post-radiation alteration is not related with endothelium-derived relaxing factor.
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MESH Headings
- Animals
- Aorta, Thoracic/drug effects
- Aorta, Thoracic/physiology
- Aorta, Thoracic/radiation effects
- Cesium Radioisotopes
- Endothelium, Vascular/diagnostic imaging
- Endothelium, Vascular/drug effects
- Endothelium, Vascular/physiology
- Female
- Isoproterenol/pharmacology
- Nitroprusside/pharmacology
- Phenylephrine/pharmacology
- Radiography
- Rats
- Receptors, Adrenergic, beta/drug effects
- Receptors, Adrenergic, beta/radiation effects
- Stimulation, Chemical
- Time Factors
- Vasodilation/drug effects
- Vasodilation/radiation effects
- Whole-Body Irradiation
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Lobanok LM, Luksha LS. [The contractile reactions of aortic segments to noradrenaline in the immediate and late postradiation periods]. Radiats Biol Radioecol 1995; 35:269-73. [PMID: 7757192] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
It is shown on isolated aorta preparations, that external gamma-irradiation of rats in dose 6 Gy results in intensification of endothelium-dependent relaxation which reaches of maximum in 30th days of post-radiation period. Constriction effect of norepinephrine on preparations without endothelium in remote terms after irradiation decreases with maximum on 90th days.
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Lobanok LM, Bulanova KI, Gerasimovich NV, Sineleva MV, Miliutin AA. [Modifying effect of incorporated 137Cs on the mechanism of adrenergic control of myocardial contraction]. Radiats Biol Radioecol 1994; 34:651-6. [PMID: 7951898] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Incorporated 137Cs (absorbed dose of 0.26 Gy) causes decrease of myocardial's contractile function and inotropic response to beta-adrenagonists effect, isoproterenol-stimulated adenylate cyclase activity and beta-adrenoreceptors affinity. Adrenergic effects, mediated by alpha-adrenergic structures on heart contractile function, on the contrary, become stronger, that is due to the increase of the receptors' density on sarcolemma surface.
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Voĭtkun VA, Miliutin AA, Lobanok LM. [Regulation of glucose transport in rat thymocytes after chronic gamma-irradiation]. Radiats Biol Radioecol 1993; 33:521-4. [PMID: 8401872] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Chronic gamma-irradiation (1 Gy, 100 mR/hr) increases cell titre in rat thymus and decreases glucose transport activation by phorbol ester. Animals kept in the Chernobyl evacuation zone over a period of 30 days exhibit reduced thymus cellularity and decreased PMA (200 nM) stimulation of glucose uptake by thymus cells.
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Lobanok LM, Kirienkov AE, Gerasimovich NV. [Modification of adrenergic regulation of heart function under effect of radio-ecological factors within 10-kilometer zone of the accident at Chernobyl nuclear plant]. Radiats Biol Radioecol 1993; 33:484-8. [PMID: 8401868] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Rats kept within the ten-kilometer zone of Chernobyl disaster over a period of 30 days exhibited a decreased heart function response to beta-adrenoreceptor stimulus, reduced density of the receptor structures in cardiomyocytes and their affinity to specific agonists. The number of beta-adrenoreceptors in myocardium cells was restored in 6 months, but their affinity and heart function response to the effect of beta-adrenoagonists remained decreased. No significant changes were observed in regulation influenced indirectly via alpha-adrenoreceptors.
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Miliutin AA, Kirpicheva TM, Lobanok LM. [The effect of incorporated cesium-137 on the structure of the erythrocyte membranes]. Radiobiologiia 1993; 33:302-6. [PMID: 8502752] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The influence of incorporated cesium 137 (the absorbed doses of 0.26-0.08 Gy) on the erythrocyte membrane structure has been investigated. It has been shown that chronic internal exposure to gamma radiation causes structural reorganization of erythrocyte membranes at remote postirradiation times (in 3 and 6 months) that influences the annular membrane lipid.
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Kirienko AE, Petrashevskaia NN, Lobanok LM. [The adrenergic regulation of cardiomyocyte electrophysiological activity, cardiac biochemical function and coronary blood flow in rats with incorporated 131I]. Biull Eksp Biol Med 1992; 114:340-3. [PMID: 1288679] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The study was made of the rat heart isolated according to Langendorf and right auricles. Intraperitoneal injections of 2.5 MBq/kg 131I were performed. Electrophysiological and biomechanical myocardium response to stimulation of alpha and beta-adrenoreceptors with isoprenalin and phenylephrine hydrochloride was analyzed. Postradiation modification of adrenergic control in animals with incorporated 131I appeared as reduced functional response of cardiomyocytes and intact heart to beta-adrenoagonist and enhanced response to alpha-agonist was detected.
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Shilov VV, Lobanok LM. [Adrenergic control of myocardial contractile function in rats with incorporated 137Cs]. Radiobiologiia 1992; 32:143-7. [PMID: 1314397] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
It was shown on isolated myocardium preparations that internal gamma irradiation of rats with 137Cs (1.6 MBq/kg) decreased the contractile function of ventricles and had no essential effect on the auricle contractility. The inotropic response of myocardium to activation of alpha-adrenergic receptors decreased, and of beta-adrenergic receptors decreased.
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MESH Headings
- Animals
- Cesium Radioisotopes/adverse effects
- Dose-Response Relationship, Drug
- Dose-Response Relationship, Radiation
- Female
- Isoproterenol/pharmacology
- Myocardial Contraction/drug effects
- Myocardial Contraction/physiology
- Myocardial Contraction/radiation effects
- Phenylephrine/pharmacology
- Propranolol/pharmacology
- Radiation Injuries, Experimental/physiopathology
- Rats
- Receptors, Adrenergic, alpha/drug effects
- Receptors, Adrenergic, alpha/physiology
- Receptors, Adrenergic, alpha/radiation effects
- Receptors, Adrenergic, beta/drug effects
- Receptors, Adrenergic, beta/physiology
- Receptors, Adrenergic, beta/radiation effects
- Time Factors
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Vinogradov VV, Galitskiĭ EA, Nadol'nik LI, Beluga VB, Lobanok LM, Rusiaev LA, Fedorovich VA, Ulinskaĭte AP. [Adrenal functional activity and hormone-protein interactions in coarctation of the abdominal aorta in rats]. Patol Fiziol Eksp Ter 1991:28-30. [PMID: 1798647] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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Shilov VV, Lobanok LM. [Modification of the chronotropic-inotropic relations in the atrial and ventricular myocardium during external gamma-irradiation]. Radiobiologiia 1991; 31:432-5. [PMID: 1887014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
It has been shown of isolated muscle preparations of rat heart that external gamma-irradiation with a dose of 6 Gy reduces the contractile capacity of myocardium and changes the chronoinotropic relationships: in the auricle, the rate/power relationship and the potentiating effect of the passive interval increase, and in the ventricles, the potentiating effect decreases. Modification of the chronoinotropic relationships may be associated with changes in the calcium ion transport in the heart cells.
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Sineleva MV, Lobanok LM. [The short-term and long-term effects of gamma-irradiation on the inotropic reaction of the myocardium during the activation of alpha- and beta-adrenoreceptors]. Radiobiologiia 1990; 30:491-5. [PMID: 2171010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The contractile function of myocardium was impaired and its inotropic response to stimulation of alpha- and beta-adrenoreceptors decreased at early times (1-30 days) following whole-body gamma-irradiation with a dose of 1.0 Gy. Six months after irradiation the response of the isolated myocardium to stimulation of adrenoreceptors increased to exceed that of intact animals. In a year the reactivity of the myocardium towards alpha-adrenoreceptor agonists remained high and its sensitivity of phenylephrine hydrochloride increased considerably; the response to beta-adrenoreceptor agonists was virtually absent.
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MESH Headings
- Animals
- Cobalt Radioisotopes
- Female
- Gamma Rays
- Isoproterenol/pharmacology
- Myocardial Contraction/physiology
- Phenylephrine/pharmacology
- Radiation Injuries, Experimental/physiopathology
- Rats
- Receptors, Adrenergic, alpha/drug effects
- Receptors, Adrenergic, alpha/physiology
- Receptors, Adrenergic, beta/drug effects
- Receptors, Adrenergic, beta/physiology
- Stimulation, Chemical
- Time Factors
- Whole-Body Irradiation
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Miliutin AA, Voĭtkun VA, Lobanok LM. [The effect of low doses of gamma radiation on the structural-functional status of the membranes of aortic smooth muscle cells in rats]. Radiobiologiia 1990; 30:54-6. [PMID: 2156281] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Using the fluorescent probe and membrane filtration methods it has been shown that 3 days after gamma-irradiation of rats with a dose of 1 Gy microviscosity of membranes increases and their Ca2(+)-transport function decreases with a simultaneous increase in the affinity of Ca2(+)-pump for calcium. In 15 days, the characteristics under study do not differ from those of the intact controls.
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Lobanok LM, Kirienkov AE. [Age-related characteristics of cholinergic regulation of the biomechanical function of the rat heart in hypoxia]. Fiziol Zh (1978) 1989; 35:65-9. [PMID: 2721746] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Hypoxia is shown to decrease chronotropic and inotropic responses of the isolated heart of mature rats to stimulation of M-choline receptors. In aged tissue hypoxia has no influence on the inotropic response to carbocholine effect. The results permit a conclusion to be made on the higher resistance of cholinergic mechanisms that regulate the cardiac function to hypoxic effects in aged animals.
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Lobanok LM, Kirienkov AE. [Age-related characteristics of adrenergic regulation of the contractile function of the heart in hypoxia]. Kosm Biol Aviakosm Med 1988; 22:64-8. [PMID: 2852277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Experiments were performed on isolated hearts of adult (8-10 months old) and aged (24-26 months old) rats perfused with the Krebs-Henseleit solution according to the method of Langendorf. It was demonstrated that when oxygen supply was insufficient (pO2 of the perfusion solution-100 mm Hg), the chronotropic reaction of the heart to the stimulation of alpha- and beta-adrenergic receptors with phenylephrine hydrochloride (5 x 10(-7)--10(-5) M) and isoprenaline (10(-9)--10(-6) M), respectively, increased in adult rats and decreased in aged animals. Positive inotropic effects of adrenoagonists in hypoxic hearts diminished but their values as well as those at adequate oxygenation (pO2 = 600 mm Hg) were higher in aged rats. Stimulation of adrenoreceptors in the case of inadequate oxygenation increased hypoxic myocardial contracture, the increase being greater in adult rats.
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Lobanok LM, Kirienkov AE. [Characteristics of the effect of hypoxia and reoxygenation on the contractile activity of the isolated heart in rats of various ages]. Kosm Biol Aviakosm Med 1988; 22:70-2. [PMID: 3379905] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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Lobanok LM, Kirienkov AE. [Age-related characteristics of the effect of hypoxia and reoxygenation on the contractile function of the isolated heart]. Patol Fiziol Eksp Ter 1988:52-5. [PMID: 3362591] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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Lobanok LM, Sineleva MV. [Mechanism of self-regulation and the inotropic reaction of the rat myocardium during aging]. Biull Eksp Biol Med 1987; 104:526-8. [PMID: 3676481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The experiments on rat papillary muscles revealed that in ageing rats myocardium has a decreased distension ability. The curves of shortening value/length and force/velocity for the myocardium of old animals are shifted downwards. The alterations in isotonic contraction parameters had a distinct age differentiation, while the age did not affect the inotropic effects of increased frequency, paired stimulation and external calcium. It is suggested that changes in biomechanical properties of ageing myocardium are associated with alterations in calcium transport in sarcoplasmic reticulum.
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Lobanok LM, Shilov VV, Kiriliuk AP. [Effect of calcium on the force-frequency ratio and resting potentiation in the myocardium of mature and old rats]. Biull Eksp Biol Med 1986; 101:261-3. [PMID: 3955203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The studies on the isolated papillary muscles have shown age-dependent differences in the tension developed, the rate of its development and decline in adult (10 months) and old (27 months) rats at 0.1 Hz stimulation frequency and different concentrations of external calcium (0.3, 1.25, 5.0). With 0.3 mM of Ca2+ in the solution, the negative inotropic frequency effect, and resting potentiation of contractions (interstimulus interval 30 s) in the myocardium of old rats were considerably lower than those in adult animals. Calcium level elevation (5.0 mM) resulted in elimination of frequency inotropic effect and resting potentiation in the rat myocardium in both age groups. The abnormalities of chronoinotropic relations in the myocardium during aging can probably be explained by the changes in Ca2+ transport.
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Arinchin NI, Lobanok LM. [Correlation between mechanical and electrical ventricular systoles during critical acceleration of the heart rate]. Kardiologiia 1972; 12:139-40. [PMID: 5016702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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